Apparatus for drawing projections



Oct. 13, 1959 P. w. suNDsTRM 2,908,078'

APPARATUS FOR DRAWING PRoJEcTIoNs Filed nec. '7, 1955 s sheets-sheet 1 /M A 7 TORNE Y Oct. 13, v1959 P. w. suNDsTRM 2,908,078

v APPARATUS FOR DRAw'ING PRoJEcTIoNs Filled neg. 7, 195s ves sheets-sheet 2 IN VEN TOR Arromvfr P. w. sUNDsTRM APPARATUS Fon DRAWING PRoJEcTIoNs Oct. 13, 1959 6 Sheets-Sheet 3 Filed Dec. 7, 195s,

* ATTOkA/fr P. W. SUNDSTRM l APPARATUS FOR DRAWING PROJECTIONS Oct. 13, 1959 6 Sheets-Sheet 4 Filed Dec. 7, 1953 97 l y /NvE/vro/P v @la/m f/W Arron/Er Oct. 13, 1959 P. w. suNDs'rRM 2,908,073

APPARATUS FoR DRAWING y1 Ro.mc'r1oNs Filed nec. 7, 195s e sheets-sheet 5 J Q2 /f WIW L@ INVENT P. w. suNDsTRM 2,908,078 APPARATUS FoR DRAWING PRoJEcTrpNs Oct. 13, 1959 6 Sheets-Sheet 6 Filed n ec. '7 1953 United* States Patent APPARATUS FOR DRAWING PROJECTIONS Per Willehard Sundstrm, Stockholm, Sweden, assignor to Rudolf Hohndahl, Stockholm, Sweden Application December 7, l1953, Serial No. 396,384 Claims priority, application Germany July 4, 1953 9 Claims. (Cl. 33-18) This invention relates to apparatus for drawing projections and particularly for drawing central perspective representations.

It is an object of the invention to provide improved apparatus for correctly producing a perspective view from any subject or representation.

Another object o-f the invention is to provide an apparatus for producing plan views from perspective views.

A further object is to provide an apparatus which can easily be modified or adjusted for many Various uses.

The novel features lwhich I believe to be characteristic of my invention are set forth Iwith particularity inthe claims. The invention, together with .the above and other objects and advantages thereof, will be better understood by reference to the following description taken in connection with the accompanying drawings forming part of this speciiication, and of which:

Fig. 1 is a diagrammatic view showing the principle of the invention.

Fig. 42 is a view taken along the line II-II in Fig. l.

Figs. 3 and 4 are likewise diagrams of the principle of an apparatus adjusted for enlarging pictures.

Figs. 5 and 6 are diagrams showing the adjustment of the same apparatus when it is intended for drawing reiiected images.

Figs. 7 and 7a are perspective views which, when taken together, illustrate apparatus according to the invention.

Figs. 8, 9 and 10 are details on a larger scale of the bearing arrangement in the viewing centers.

Figs. 11 and 12 are details on a larger scale of the bearing sliding on the axle and connecting the two links.

Figs. 13 and 14 show details of an arrangement marking the projection in the plane of the object table of the viewing center.

Figs. 15 and 16 show a ing direction bar.

Fig. 17 is a perspective view of part of the apparatus and showing a means for keeping the pin lifted and inactive and making it active when desired, and

Fig. 18 is a sectional view through a housing on the vertical screw for the height adjustment of the frame carrying the two centers, in which housing a gearing is arranged. Y

In Fig. 1 a xed horizontal drawing board for the object is delined by a plane 11. A pair of vertical guides 12, 13 are tixedly connected in position in relation to this board or the feet thereof (not shown). A U-shaped horizontal frame 14 is movably mounted along the guides 12, 13 by bushings 15, 16. At the branches 17, 18 of the frame 14 two bearings 19, 20 are arranged, in which an axle 21 is rotatably mounted. The ends of the axle 21 carry forks 22 and 23 having bearings 24, 25 and 26, 27 in which axles 28 and 29 are rotatably mounted. The axle 28 carries a bushing 30, wherein a viewing direction bar 31 is so mounted, that it is longitudinally and angularly movable through a point 'which is situated in the extension of the axle 21.

The axle 29 in a similar manner carries a bearing 32,

pilot pin connected to the view- ICC through which a drawing bar 33y is longitudinally and angularly movable in a point on the extension of theV The lower end of the drawing bar 33 is provided with*v a drawing means 36 which, by the movements of the viewing direction kbar 31, is brought to produce a centrally projected vew'on a paper at the projection board 37 corresponding to the object on the board 11. `The two boards are situated in parallel planes which are suitably horizontal. The horizontal projection board 37, which in the following is called picture plane is movable in the vertical direction' with the aid of guiding means 38 at the guiding bar 12. The picture board 37 is further connected at an adjustable distance to the U-shaped frame 14 by a rod 39. By this arrangement it is achieved that the projection center 35 overy the picture board 37 is constantly situated at the same height over this board, if desired, while the projection center 34 can be raised or lowered in relation to the subject table 11. The importance of this arrangement will appear in the following description of the manner of working of the apparatus.

Every movement of the bar 31, however, is not transmitted to the drawing means 36 by the arrangement described above. If for instance the point 40 of the bar 31 is moved in a plane passing through the axle 21 and the bar 31, only the axle 28 will be pivoted in its bearings 26, 27. In order to obtain a complete transmission ofthe angular movements of the bar 31 to the drawing bar 33 the apparatus is provided with special means.

On the axle 21 a sliding bearing 41 is mounted which carries ltwo sleeves 42, 43 with arms 44, 45 iixed thereto. The arm 45'is lixed to a rod 46 which is kept parallel with the axle 21 by a bearing 47 on an arm 48 preferably perpendicular to the axle 21. In a way similar to that described inV connection with the axle 21, the rod 46A the center 34 which is kept lixed in space. 'Ihe bar 31 4 may, however, be brought to any angular position. The point of intersection between the bar 31 and the rod 46 can be brought to any position on a cylinder, the axis of which is represented by the axle 21. This means that the bearing 41 will slide longitudinally and turn around the axle 21 with the arm 45 perpendicular to the axle 21 and the rod 46 making similar movements.

In order to transmit the movements of the bearing 41 to y'the bar 33 a similar arrangement is made in the lleft side of the system. To the sleeve 42 an arm 44 is connected. This arm is connected to a `rod 54 parallel to the axle 21 and the same distancetherefrom as the rod 46. An arm 55 is lixed to the axle 2l and provided with a bearing 56 in which the rod 54 is longitudinally movable. The rod 54 is provided with a fork 57 with bearings 5S, 59 for a transverse axle 6,0 i with a bushing 61 wherein the drawing bar 33 is axially movable. The distance from the projection of the intersection between the rod 54 and the bar 33 to the intersection between the rod 46 and the bar 31 is equal-l to 3 line from the eye point perpendicular to the projection Patented Ocala, lesa Therefore' the plane 37 through the axle 21 and the rod 46paralle1 thereto is arranged to intersect the plane 1,: however, the projection plane 37 is horizontal.V

through the axle' 21 and the rod `54 likewise parallelV thereto Vatan angle of 490 corresponding to thev angle between the real head line andthat against the projection plane vof.- the apparatus; Under such circumstances theprojection of the viewing. direction bar 31 in aY planeI perjggendicular4 tothe axle 21 intersects the projection of the bar 33 inthe'same plane under an angle of 90, asV

best seen in Eig. One couldA arrange the projection plane `verticallyandintersecti-ng the viewing direction in which: the bar 31 (moves. As this would be very impractical.' the plane 37vand the sight line representing means 33haveV been arrangedv beside the object table Jand 'the viewin'gcenter 34 and instead i-n `connection the 4center 35.

l planes referredtovr above are angularly adjustable, as b est seen inFigs. 7, 1l and 12, Figs. 7 to 18 showing apractical embodiment of the invention.v According to Figsell and 12 the Afsleeves 42`and 43 slide on the axle 21. The sleeve `42 has' an index 62- andl the sleeve 43 an angular graduation. The sleeve 43 partly overlies tlesleeve 42 and with a screw 63 the sleeves 'can be locked any angular position relative to eachv other. The fork 22 in Fig'. 7 is iixed to the axle 21 but the fork 23l isV arranged to follow the sleeve 42 by the angular adjustments and is thereafter llocked in position by a nut 64 on a threaded part of the axle 21.

n In Vcases where the headline is not horizontal, as,

when* the object has a relatively great extension above or below the horizontal .plane throughwthe eye point, the picture plane should not be vertical.` The angle between the real lhead line and 'the vertical line perpendicular to the Apicture plane in the apparatus has to be taken into consideration. This is made by a simple adjustment of the sleeves 42', 43 and the fork 2 3. The angular adjustment can also be changed for other purposes to be de,- scribed hereinafter. i

In Figs.y 3 'and 4 anadjustment of the angular relation is shownv which is suitable for enlargement purposes. Theliiiks 54 and '4'6 are arranged in the same line. The drawing to be reproduced in another scale is placed on the 'ohjeetvboard under the center 34. The scaleof the reproduction depends on the relation between the heightfdf center over table 37 and the height of the center 34 over table Y11`. Y K

When a re'ected picture -is desired the rod 33 is pulledy out fromthe bearings 32` andn 61 and inserted in the opposite directio`i1. The' sleeve and the nut 64 are unlocked andthe link 54' is turned t`o a position in which it Ysituated in the saine-plane Aas the axle '21 and the lik"4'6 but on the opposite side of the axle 21 as shown in Figs. 5 and 6. When the viewing direction bar 31 is ved clockwise after llocking the details in these positions'ifn Fig'. 5 the drawing bar 33v will be moved in an anticlockwise direction.V A reected picture is thus obtained. Il there is a transparent drawing'face iup on object table 11 'a 'reverse View is obtained on projection or picture 'table 37 corresponding to this transparent drawing being sketched at 'the outer side and moved over toftable 37, as when reading a book. By changing the heights from tables to centers different scales can be obtained. YThe method of obtaining rellected views can be used when 'pa'r't 'of a drawing has to be turned over.

For raising and lowering the frame 14 and thus changt ing the` height of the projection center 34 over the object tabl'e' 11, a screw "65 is arranged parallel to the vguides 12, 13 and gearing '6'6 i'n a housing 67 is provided below the table 11 '(Figs. 18.). VThe gearing is actuatedY by a shaft A68 passing through openings in two of the le s 69, org crank 71 in front of the table 11. The housing 67 rests on a pipe 72 having a foot 73 with three arms provided with adjustment screws 74. The table 11 is detachably connected to other parts of the apparatus by a connecting member '75 and screws under the lower horizontal end`parf-7`6 for the guides 12, 1-3.

VThe screw 6 5 is mounted between two 70 of the object table 11 and having a handleV balls 77 rest-,

ing eny a spherical surface in: a ball holder "78" inserted in the bottoni 791er trie housing 67' and the upper horizontal end member 81) fior the guides 1'2, .13'. A-t each end of the screw 65 a radial thrust bearing also is`arranged.- The housing' further wmprises a cylindrical, vertical wall V82 and a cover 83. The shaft 68 has a bearing 84 in a member 85 attached to the housing 67.V A threaded member 86 is xed to the frame 14 and thus the. frame 14 is moved in one direction orthe other when the handle 71 isV actuated clockwiseor in the opposite direction. n

In order to allow the viewing direction bar 31jto be movedl also in ahorizontal position the arm 18y of the' frame 14v has a curved shape.

Some detail-s of the bearing arrangement'for the view-- are arngedon which thebearing body l8'9 is `pivotal in a ing direction bar 31v and the drawing bar 33 are shown-l plaine.- The bar 31 is kept in a very de'nite position inthe body '89 by two sets of ball bearings, oneofrwhrich is shown in detail in- Fig.y 10. "In 'a .plane `perpendicular to. the bar 3'1' three ball bearings v90 are insertedthroughl openingst91 in the body '89 and carried on axles 92 in- .serted through smaller openings 93 andvpos'itioned byl distance rings 94, 95 and 96. The openings 91 and 93 are covered by du'st protecting rings 97.

The guiding arrangement for the bar 31`is of a nature which makes the bar 31 movable essentiallyronly in the .longitudinal direction. The bearings 53 and- 61 are of a similar construction' having, howevenonly one set of ball bearings. In orde-r t'o make'it; possible to keep the point of the har 31 directed to the object without changingL the grip thereon when the baris moved, the bar can beprovid'ecl witha point member whichcan be tur-nedwithin the bar 31which is 'in the formof apipe.

lIn many cases when the-object is represented by aYY horizontal section andthe bar-31 is to be moved very near the corresponding horizontalplane, it would be very inconvenient to work withy the bar 31` in the formA hitherto described.v InsteadY aU pilot pin 98 is used which is coninected to the point of the bar 31 and so arranged that it can be constantly kept perpendicular to the table 111.

This arrangement is shown in Figs. 7A, 15 and 16. In the end of the bar -31Y a plug 99 is arranged to be turned around'. This plug is connected to kthe pilot pin98- by an axle 10U. Y In this waythe pilot pin98-can be moved .into

every 4position. with relation to the'ibar 31.- [he pointfof intersectidn between-the center lines for the bar 31g-and the .pin 98 is 'the point-which determines `theviewirlg direc'tion fromthe projection center 34. This poi-nt is:

constantlymovedin aplane .parallel-V t'o the' table and thus :the real section! is reproduced as seen from-the 'oenter 34. and situated on higher 1evel. The pin 98-isfkept t perpendicular to' thetable- 11 by-a preferably transparent' plate with ,four legs V15022.- TQ-keep the pin 98 slight-lyabove the ytable in-order'notto ,tear a' paper thereon, it is. connected to the vv.plate-101 by ajsleeve 163 and ,pref-f erablyasnap acting member 104.- When for' instance right -angle lines'onjthe` table 11 are tov be reproduced' this can4 be facilitated `ifa rule cani beu'sed for guiding the .pin98-f `Forithat, reason: they pilot pin ,9SA isarrangedY vel-ysearthe margin' of thej plate 101.

The drawing bar=33 is .provided with an `arrangenient i to counteract the weight thereof fand kkeep thedrawingu` means out of contact` with the table V3,7 orf-a paper placed thereon. This arrangement is shown in Figs. 7 and 17. In Fig. 17 part of the machine isY shown in dotted lines. A wire 105 is attached to the upper frame member 80 and passes in a vertical direction down to a roller 106 journalled on a screw on the rear side of the fram-e 14. Fromvtheroller 106 'the wire extends to another roller 107 on an auxiliary arml 108 attached to or forming part of the frame 14 and to a roller 111 on the rear arm of the,

fork 23 and down rto a roller 110 near the drawing means of the bar 33.' .The wire then goes up to a second roller 109 which is rotatable on the same axle as the roller 111. This axle, not shown in the drawing, is arranged in a pivotal member attached to the fork A23. Hence, the Wire may change direction when the bar 33 is moved, without leaving the rollers 109 and 111. From the roller 111 the wire passes to a -second roller 112 at the end of the auxiliary arm 108, through a hook 113 at the free end of a spring 114, the other end of which is attached to the frame 14. Further, the wire passes over a second roller 115 on the frame 14and vertically downward to a controlling member 116 which is shown in the form of a lever in Fig. 7. This lever carries a counterweight 117, a pedal 118 and is pivoted at one front leg 70 of the object table 11. Only when the pedal 118 is depressed the drawing means will be active during the movements of the drawing bar 33.

In Fig. 7 a vertical graduated rule 119 is shown at the right side of the two vertical guides 12, 13. This rule 119 is attached to the frame 14 and the upper frame member 80 has an'index `120 so that the relative heights of the frame 14 in different positions can be controlled.

The center 34 corresponds to an eye point from which the object is seen. The head line corresponds to the optical axis in a camera, the lens system of which is situated at the eye point. The film in the camera is perpendicular to the optical axis and corresponds to a paper on table 37. 11n order to be able to locate an object drawing so that the desired perspective view is obtained it is necessary to know or to decide the height of the camera over the ground, the distance from object to camera and the angular direction. If the object is represented in the form of a plane, as a horizontal section of a house, it is possible to decide that the camera shall be located say 20 meters from the face of the house, 5 meters over the section plane land in a direction from a point which can be marked at the drawing. From this point an auxiliary line is suitably drawn through the center part of the house.

vIf it is desired to make a drawing cor-responding to a photograph taken from the point mentioned above, the sectional drawing is positioned on the table 11 so that the auxiliary line intersects a point right under the center 34, this point being marked by a member 121 which is a projection on the plane of the table 11 of the eye point 34, as best shown in Figs. 7, 13 and 14. This member 121 might have the form of a short pin projecting from an arm 122 under the table, which normally is located in front of that point seen from the operator. The arm 122 can be moved aside, when the tableis to be pushed in under the center 34 for other purposes as enlargement work. A graduated rule 123 is arranged to be pivotally mounted on the pin 1-21 so that the graduated side gives the distance from the projected point. To the pin 121 a plate with an angular scale 124 is attached below the graduated rule r123. Y

The rule 123 is laid over the section and this is moved to or from the point 121 so that the desired distance is obtained. After that only the height of the center 34 has to be adjusted. This height can be measured by hand or on the vertical graduated rule 119 along the guides 12, 13.

A vertical plate 125 (which is suitably transparent) is attached to the frame 14 by three screws 126 visible in Fig. 7. At the upper edge of the plate 125 a paper holder 127 is shown. At the rear side of the guide `12 a 6 U-shaped frame 128 is adjustably attached, the legs of which are connected by a thread 129'in front of the plate 125. A drawing presenting details in vertical positions can be attached to the plate behind the thread.

lIf a body as a cube is to be reproduced, different methods can ybe used. -First the square on the object table could be reproduced which will result in a view ofrthe bottom plane. Thereafter the object table is raised so that the square on the object table will be situated in the upper plane of the cube nad once more the square is reproduced which will result in a View of the upper plane of the cube.

Of course one can reproduce the planes in the opposite order and lower the table between the operations of drawing. The respective cornerv points in the picture then can be connected by right angle lines drawn yby hand. Such vertical lines on the object can also be obtained by having the pen rest on the picture table and keeping the pilot pin 98 at a corner point of the object during the change of height of the table 11 in relation to the projection center 34. Since a movable working table is inconvenient, the arrangement in the preferred embodiment shown is such that the working table can be fixed.

One can obtain the same result by instead making the projection center 34 adjustable vertically and permitting the picture table 37 to accompany the center 35 in this movement. Then one can suitably begin with the reproduction of the bottom plane of the cube, thereafter lowering the frame 14 with the projection center 34 and the picture table 37 as much as the height of the cube inthe desired scale before drawing the upper plane.

It appears from the above that a body can be drawn in perspective with the aid of a number of orthogonal projections of parallel sections through the body. Of course it is possible to make perspective sections of the body in the same manner. It is only necessary to know the perpendicular distance between these sectional planes in or-A der to take this into consideration when changing the height of the center 34 ove1 the object table 11.

When planes situated below the horizonline are to be reproduced the center 34 is raised. When on the contrary planes over the same line are to be reproduced the center 34 is `to be lowered so that the viewing direc-` tion bar 31 is inclined up to the object. This is possible owing to the pilot pin 98 being pivoted to the bar 31.

lf one wishes to reproduce, for example, the faces or side of a house, it is possible to arrange the plane plate perpendicular to the object table 11 and along one front bottom line. On this plate 125 an orthogonal projection of the face or faces is attached. When 011e after a suitable adjustment of the center 34 follows the lines in the object picture on object table 11 which have to be reproduced in the perspective View with a point which may be attached to the bar 31 instead of the fork plug 99, the desired View is automatically obtained onthe picture table. Of course the object representation can instead be attached to a wall or the like in front of or behind the object table 11. Y

It is also possible to place an elevation view ilat on the object table 11 and to keep the eye point 34 in the sameangfular relation to such View, whereafter the drawing bar 33 is adjusted perpendicularly to the picture table 37. This means that the center 34 is first adjusted to a position comprising the real eye point and the bar 31 is. kept in line with the real head line during `the adjustment of the bar 33 to the angular relation which has to be used when making the reproduction.

In such elevation view the real horizon plane is vertical and intersects the object table 11 along a line which before designated the projection of the head line on the object table 11. The vertical projection or elevational View of the object is placed on the object table 11 in such a position that the direction of the head line in this projection even now coincides with the head line marked on the table.

`In another yvery suitable way of drawing houses in per-4 spective views Zai-horizontal section of the house is used and attached to the'object table 11 ina suitable position.Y

A front view'fffa face of the house is attached to theV vertical plate 125 connected to the frame `14 in a vertical an'd upright position behind the indicating, horizontal thread 129;- rPhe holder 1-28 for this thread is then lowered 'or raised' along the guide 1-2 so that the thread coincides with 'a horizontal line corresponding -to the plane of the horizontal' section on the table 11 when the center 34 is `'positioned at thepointy froin which the perspective view is to be seen. Y

-Details y'of the `horizontal section which are to be seen in the perspective ,view are drawn. Then the center 34 is lowered before details of the face, as a window, for example, is drawn. The position ofthe windofw corners can be marked 'on the line in the horizontal section which corresponds to a Vertical projection of the window."

In order to move the pilot pin v98 from the horizontal section to a corner point the pilot pin is kept at a marked point in the plan View on object table ll and the frame 14 with the center 34 is lowered until the thread 1.29 coincides with the lower line of the windowl in the elevation view.V Now the pilot pin 98 can be moved along the line to the other marked corner point with the pen in action.

If the center 34 is lowered further until thethread coincideswith the upper window line and the pen is in action, avertical fwindow line is reproduced on the table 37. The pilot pin 98 is now moved back to the first marked point on the table 11 and then the center 34 is raised the height of the window on'the elevation view. During the last mentioned movement a vertical window line from an upper to a lower corner is being reproduced.

- With the center 34 in a suitable position all horizontal lines in one `horizontal object plane can be drawn vwhen the thread 129 on -plate 12S is positioned at the 4desired vertical height on the elevation view mounted on the plate. Vertical lines can be reproduced as indicated above or drawn by hand between the end points dotted or marked off by the machine.

Y Straight lines which are not horizontal or vertical in the object can be completed correctly if only two points thereon are obtained by the machine. Otherwise, corresponding sections or plan views can be used on the object-table as described above.

IIf dilferent horizontal sections in the same house differ from each other, of course these different sections haveV to b'e placed on the object table and reproduced whereby the different sections have to be positioned correctly in Y relation to each other.

Pictures of double-curved surfaces can be drawn when a` suthcie'nt number of sections close to each other are reproduced `and thereafter the perspective picture is completed by drawing the contour lines which are tangential tot-he sections or by connecting the points which form limiting lines of the surface.' Y

When the lextension of the object in the vertical direction over the horizontal plane through the head point is .so-great thatfthe rear edge of the object table prevents a sufficient lowering of the center 34, an inverted section can be made in the machine. The bar 33 is lpulled out of the centers 35 and 61 and the center 35 and the link 54 turned 180. This change has to be made because the horizontal projection is still positioned as before. If the drawing is transparent it is only necessary to Vturn itupside down on the table.' Then the bar 33 is again inserted so that the pen points to the table.` After a suitable adjustment of the height of the center 34 the view can easily be drawn in the form of a reilect'ed picture. It is to be observed that positive heights in relation t'o the ground plan'enow are turned negative.

Hithe'rto it has been assumed, that the head line is horizontal. j j Y Theoretically, when the extension of the'object above or below the horizontal plane through the horizon line,

which may bie fat the height of the view point 34, fori example, is so 'great that the angle of view 'atsthe view point Vwillv be toogreat it ,is possible to 4iiicl'inethe head line. :(The :angle vo'fyievv 1s twice the angle compris z thegoriginai head lihe and' a line tothe anguiariysm t'. distant point 'of 'the object.) Ihthis instah'eethe lcenter- 34 -is raised lorlowered until the bar 31`w1ith the-pointat the table reaches the inclination corresponding :to

perspective views of points situated close to eachother and then viewing-them so that a person sees only' one view with his left eye fandV These 'possibilities open unexpected perspectivesin connection with the' pro` the other viewwith his right eye.

duction of motion pictureswith designed images. When making three dimensional pictures it is possible to `beginwith the two dimensional View. The rod 31 and 'the bar 33 are adjusted to an yangle of about '5 Iseen in the direction of the axle Z1. The rod 54 is moved while the rod 46 remains in a fixed position so that the angle between the Iarms 44 and 45 is changed from 90 to 270. kWithv this adjustment, the second perspective View produced Vby bar 33 is made as `seenfrom the first Veye but in `a direc-v' tion parallel to the headline for the second eye. The

distance from the object table 11 to the 'center-34 should Y be the same as the distance from the table 37 to the center'3'5. The nrst object view is placed on'the object'v table'11 with the longitudinal direction of the in the longitudinal direction ofthe table and 'at such av distance from the ground point that a vertical 'line through the center 34 intersects the `angle between the rodand the bar in two equal parts, when the `rod 33 is Vdirected to the center of the second view.

When drawing the rst picture one :assumes that dit ferent details are located at dilferent distances from the viewer. These distances should be known but they feanf be determined'by thev relationship to the size ofsome known details. The drawing suitably vbegins withthe most distant details and the center 34 is then successively lowered proportional to the distance from ther/lower. It should be observed that the distance from the center 3Svto the table l37 should be lowered equally to the `center 34.v Such change is most V'easily obtained if a'platey is arranged in the same plane vas the object table lflrand below the center 35. j

By following a circle line on the object table it is possible byV diierent combinations of the height vof lthe projection center 34, the dimensions of the eil-cle on the table 11, the distance between center k35 and the table 37, and different initial angles between the pilot rod y31 andthe pencil 33 directly to obtain ellipses, parabolasV and hyperbolas of desired form. The circle `center at the object table 11 should be situated vertically under the center 34. If the pilot poi-nt follows this circle the bar 31 will move in v-a path defining the surface of 'aconical body. Y The pen 33 will move in a path defining-a similar surface. If'the axis of this last mentioned conical surface is inclined, the intersection between this surface and the projectionplane or picture table 37 -can 'be arranged to represent any of the conical's'ections. fl'n'order to obtain a more steady circular movement of the pir-lot pin a center point can be arranged on the table so that the pilot pin can be moved around this center point at an adjustable distance.

This movement may be guided by` a gear transmission` (not shown) from the handle 71. which'is arranged under the object table 11 foradj1'1st-- ment of the height of the frame 14. If thus the move-4* ment simultaneously raises the eye point and lvc's'th'c pilot pin 98 in the circle, a perspective view of a spiral is obtained. The pitch thereof can be changed by simultaneously changing the size of the circle on the object 'table 11 and the distance from the projection centers 34 and 35 respectively to the picture table 37 or to the object table 11 or to both tables. It is also possible for this purpose to provide a device for producing a variable ratio of revolutions of the handle 71 with respect to the pilot pin 98 when describing a circle. Also, the angular relation between the bar 31 and the pen 33 can be used to produce the to above.

If the picture table 37 were movable in a transverse direction and such movement were coordinated with the rotation of the handle 71, it will be possible to draw sine curves such as the orthogonal projections of screws, for example. t n

In order to be able to make orthogonal projections from photographs of objects or to make a map from a photograph of a landscape, it is necessary to know some data. In the first case the angle between the optical axis of the camera to the 'plane of the house and also the perpendicular distance from the camera to such a plane in which an orthogonal projection is desired, must be known. Further, the actual distance between two clearly visible details in the photo must be known in order to establish a control for the scale of the required drawing.

The photograph is placed on the object table 11 with the center point thereof vertically under the center 34 if the optical axis of the camera was horizontal at the time of exposure, so that the center point of the view is directed to the operator. The rod 31 and the bar 33 are then adjusted to the given angle referred to above. The center 34 is then adjusted to a height equal tothe focal distance f of the camera. If the photograph is of a small size it is enlarged and the height of the center 34 is increased proportionallyto the scale of the enlargement. The distance from center 35 to the picture table 37 is adjusted in the scale of the desired projection to be equal to the distance from the camera to the reproduced plane. The scale is controlled in the following manner. The point of the pilot pin 98 is moved over the known distance. The line s in the view at the picture table 37, which is the projection of the known distance, is measured. This line, by reason of the scale selected, should be of the length s1. In order to obtain the right scale on the projection or picture table 37, the distance from the center 35 to the tableV 37 is multiplied by and the new height is adjusted.

Maps can be made from aerial photographs with respect to known elevations on the ground.

When usingaerial photographs it is necessary to know the nadir distance, subtended by the angle between the vertical line through the camera and the optical axis of the lens.

The photograph is placed on the object table 11 with the center point of the picture vertically under the center 34, so that the nadir is directed from the operator. The

dierent conical sections referred- Y If the desired scale on the projection table 37 is called b, the distance to be adjusted between the projection table 37 and the center 35 is in A- f, being the focal distance of the camera. As, however, the scale of the photograph is not quite the same throughout the picture a readjustment as described above might be necessary. n v

' When now the point of the pilot pin 98 is moved along the lines of the photograph a map in jan even scale is obtained on the projection table 37. This method, however, is only to be used when making maps over an even landscape, sea shores and the like.

As the aerial photograph is a perspective view, heights are radially displaced from the center of the picture.

This displacement becomes greater with increase in height v and increase in distance from the center of the photograph. If, however, the differences between the levels are known, it is possible by a vertical adjustment ofy the center 35 in relation to the height in the scale of the photograph to make a correct map also of an uneven landscape. As it isnot so easy to adjust the center 35 over the projection table 37 as it is to adjust the center 34 over the object table 11 it is possible to place the photograph on the projection table 37 and arrange ya drawing means at the bar 31. Then the center 34 is adjusted to correspond to the different heights land the map can be drawn on the table 11. By interpolation of heights in parts between known heights, approximately correct situations also for points in these parts can be obtained. v i

When using photos taken from points on the ground the optical axis is either horizontal or slightly declined. The method to be used is the same as in the case of aerial views. The rod 31 and the bar 33 `are adjusted -to an angle equal to the angle between the vertical line and the optical axis.

Aerial views are often used as maps for purposes of recognition. From these, however, no indication of the height relations of the landscape are obtained. With the apparatus according to the invention, it is possible to -transmit contour lines from a map to a photograph in such a way that the contours are situated in the correct position relative to the details of the View even if these contours due to perspective distortion are somewhat displaced.

Firstly the scale of the picture is decided and the rod 31 and the bar 33 adjusted to an angle defining the nadir distance. The distance from the center 35 to theA projection table 37 is adjusted to the focal distance of the camera. The photograph is placed on the projection table 37 with the center of the picture vertically under the center 35 and with the nadir distance directed perpendicularly to the rear edge of the projection table 3'7. y

The distance between the center 34 and the object table 11 is adjusted relative vto the distance from the center 35 to Vthe projection table 37 to correspond to the relation between the scale of the map and that of the photograph. Then the map is placed on the table 11 so that when the point of the pilot pin 98 is placed on a point of themap, the drawing rneans of the bar 33 is directed to the same point in the picture. The map can now be turned around this point so that the point of the bar 31 and that of the rod 33 are directed to the same point in the diterent representations.

Now the map and the photograph are oriented to each other. A readjustment as described above might, however, be necessary. It should be observed, thatV the' ser* most' 'contour line 'ori 'the inap Vand this line is followed by the point of the pilot pin '98. Then the frame 1.4 vis lowered Vfor the drawing of the next contour line and so Althoughl have shown and described a, particular embodiment of myjinventi'om it will be obvious to 4those t skilled 'in Vthe a1-'t that 'various ,changes and modifications maybe made without departing Yfrom the spirit and lscope of the inventiomas pointed out in the following claims;

l' What is claimed is:

` 1. Apparatus for making a perspective drawing of an object comprising projection center structureY providing primary and secondary Vprojection centersY which "are spaced `apart and "in ktixed relation with respect to one another, means providing a first horizontalsurfac'e upon which `plan viewfdata of the object is adapted to be placed, rst movable structure mounted vfor universal movement about saidV primary projection center, said first movable structure including contour following means for following the contour. of a plan view ofthe' object on said first horizontal surface, means providing a` second horizontal Vsurface upon which the perspective drawing isV adapted to be made, second movable structure mounted for universal movement about 'said secondary projection` center, means for transmitting'movement from said rst to' said second movable "structure, said second movable structure including point marking means for marking off at said second horizontal surfacepoints whose positions are determined responsive to movement of said second movable structure, a plane parallel to said nrs-t horizon-V tal surface and passing through said primary projection cen-ter also passing throughV said secondary projection center, and means for moving said first horizontal surface and said `projection Vc'ente'r structure relative to one another to vary the perpendiculardistance between said first horizontal surface and the plane parallel thereto which'passes through both Vof 4said projection centers,

said rst and second movable structures being soangulaily displaced 'with respect to one yanother that a plane passing through said contour 'following means -landV through the axis through both of vsaid projection ycenters will beangularly displaced Vwith respect to a'pl-ane passing through said point marking means and through the axis throughtboth of said projection centers. t

2'. Apparatus as set forth in lclaim l'in which 'said meansfor transmitting movement from said first movable Istructure Ito said second movable structure includes provisions for adjustingjan'gular positions of `said rst and second movable structures with respect to one lanother about 'the axis passing through both of ysaid projection centers. *n

3. Apparatus as set forth in claim l which includes means for adjusting the angular positions of said rst and second movable structures with respect Ito one another about the axis passing through both `of said projec'tion centers. Y p

4; Apparatus as set forth `in claim l in which said -first horizontal Vsurface isV readily accessible at theV front of the apparatus and a vertical Vline passing through said primary projection center is nearer to the rear edge'than Y to the forward edge/0f said first horizontal surface.

'5. Apparatus as set forthintclaim-ll including a Vmeasuring rule overlying saidrifirst horizontal surface,Y and means for mounting rsaid rule for pivotal movement about an axis below saidiprimary projection center yand through which the iverticallinefpasses. f

in claim f6. VApparatus as set fo th 1` which includes nean's for 'holding an elevation view of an object, indieating meanscooperating with said holding means, said` means formoving 'said lir'st horizontal surface and said projection eenterfstructure relativeto one Vanotheralso effecting movement ofY vsaid holding means and sai'dinditive-to one another.V

catingmeans re A 7, pparatus' -`asjset forth in claim comprising means including a Vve'ntic-allymovable member-for carrying said lprojection center structure, said means for moving said. ftrst horizontalsurface and said projection center structure` rela-tive to one another comprising mechanism for *movi-ng said vertically movable member, verfi'call-yi disposed means for holding an elevation view of 'theVV object in an upright position, said last-mentioned being carried by said member vand movable vertically therewith, stationary guide means along which said niember is vertically movable, and -an indicator carried by said guide means ata fixed .level -at the immediate vicinity of Ysaid holding means, said holding means movin'givith respect to -said Vindicatcirvvhen movement is imparted -tov said member.

8. Apparatus for malcing a perspective, drawing Y'of anY object `comprisingprojection center structure providing" primary and secondary projection centers which are spaced apart and in xed relation Ywith respect to `one another, first movable structure mounted for universal movement about said primaryprojec'tion 'centerjand projecting upwardly therefrom, means providing a rstlhorizont'alsurace upon which plan viewi'da'ta of thefobjet is adapted to be placed, said first movable structure V'ircluding elongated contour follow-ing means having Van end 'portionrfor 4followingthe contour ofa plan view ofthe object on said 'r'st horizontal surface, such end por--` tion bei-ng movable lfrom and toward said pro-y jection center, second movable structure mounted v'for'Y universal movement about said secondary projection center `and projecting upwardly therefrom, means providing a rsecond horizontal surface upon whichA the perspective drawingv is adapted to be made, said second movable structure including elongated point marking means hav-` ing an end portion adapted ylto produce a mark `at said second horizontal surface, the end portionof Isaid lastmentioned elongated point marking means being-movable from and toward said secondary projection center, m'e-V chanical means for ltransmitting movement from a region of said first movable structure above said `primary pro'-I jection'center to-aa, region of said second movable structure above said secondary' projection center, l*aV plane said contour following means and through the axis through both of said projection centers will be angularly `displaced with respect to a planeV passing throughsaid point marking means and through 'the axis through of said projection centers, Vand rmeans for moving saicl rst horizontal surface and vsaid projection "center 'structure relative 'to one another to vary the perpendicular distance between said first horizontal surface fandthe plane parallel thercfo which passes through bcthof said" projection centers. t t, 9..,Ap'paratu`s formaking a'perspec-t-ive drawing of an object comprising projection center structure providing'- primary and secondary projectionV oentersfwhich*are` t spaced apart' and in xed relation with respect to one another, first movable structure mounted for universal movement about said primary projectioncenter andprojectng upwardly therefrom, means providing 1a first horizontal surface upontwhichplan view data of theJobj'ect is adapted Itolbe placed,said `rst Vmovable jstrufc'tre' including 'contour following means'adapted to be positioned at a multiplicity of points on the contour of @a view ofthe Yobjecten said 'first horizontal surface, second movable structure mounted for'ur'iiversal movementabout said secondary projection center and projecting-'upward 13 ly therefrom, means providing a second horizontalsurfacerupon which the perspective drawing is adapted to be made, said second movable structure including point marking means yadapted to produce a mark at Asaid fseeond horizontal surface, mechanical means for transmitting movement from =a region of said iirst movable structure above said primary projection center to a region of said second movable structure above said secondary projection center, `a plane parallel -to said rst horizontal surface and passing through said primary projection center also passing through said secondary projection center, the parts of said rst and vsecond movable structures above said projection centers being `so angularly displaced with respect to one another that a plane passing through said contour following means and through the axis through 'both of said projection centers will be angularly displaced with respect to a plane pass! ing through said point marking means and through rthe axis through Iboth of said .projection centers, land means for moving said :first horizontal `surface and said projection center structure relative to one another to vary the .perpendicular distance between said first horizontal surface Iand the plane parallel thereto which passes through both of said projection centers. n

References Cited in the le of this patent UNITED STATES PATENTS 398,865 Wade Mar. 5, 1889 704,307 Eichenberger July 8, 1902 1,452,858 Wetzer et al. Apr. 24, 1923 1,617,632 Gillespie Feb. 15, 1927 2,419,610 Waldorf Apr. 29, 1947 2,615,251 Edmunds Oct. 28, 1952 2,746,152 Deakin May 22, 1956 2,766,528 Waldorf Oct. 16, 1956 FOREIGN PATENTS 287,324 France Mar. 30, 1899 109,960 Gennany Apr. 18, 1900' 29,233 Great Britain 1911 

